Expression of Alpha-Crystallins in Human Sebaceous Carcinoma of the Eyelid

Abstract

Crystallins are molecular chaperones that protect various cells from apoptosis. This study used immunohistochemistry to examine the expression of alphaA-crystallin and alphaB-crystallin in human sebaceous carcinoma tissues. Nine patients with sebaceous carcinoma of the eyelid underwent excision of the eyelid or orbital exenteration. Formalin-fixed, paraffin-embedded tissue sections were submitted for hematoxylin-eosin staining and immunohistochemistry with anti-alphaA- and alphaB-crystallin antibodies. In the noncancerous eyelid, crystallins were weakly and homogeneously expressed in the Meibomian gland lobules. In eyelids with sebaceous carcinoma, alphaA-crystallin and alphaB-crystallin were highly expressed in 4 cases, where the cytoplasmic immunoreactivity was heterogeneously detected in the tumor cells. Three and 2 cases were shown to express low levels of alphaA-crystallin and alphaB-crystallin, respectively. A statistically significant correlation was observed between expression levels of alphaA-crystallin and alphaB-crystallin in sebaceous carcinomas (p=0.012). All sebaceous carcinoma tissues contained mitotic tumor cells, which showed predominantly perinuclear immunoreactivity of alphaB-crystallin. The mitotic rate of tumor cells was 5.85+/-1.76 and 10.72+/-1.64 in high and moderate/low alphaB-crystallin-expressing cases, respectively. The number of mitotic cells was significantly higher in moderate/low alphaB-crystallin-positive than in high-positive cases (p<0.01). Crystallins are expressed in human sebaceous carcinomas including mitotic cells. Expression of alphaB-crystallin correlated with low number of mitotic tumor cells, suggesting that alphaB-crystallin may play a potential role in the regulation of tumor cell proliferation.